Find set of cells connected by pit fields between their common longitudinal walls
Companion cell and phloem fibres
Companion cell and sieve tube
Sieve cell and albuminous cell
Sieve tube and phloem fibre
Aerenchyma is formed in the tissue of
$A$ : Bast fibres are collenchymatous fibres.
$R$ : Fibres are absent in secondary phloem.
Passage cells are thin walled cells found in